Oh no, not at all, especially my main character hahahaha.
The gap between his original concept and what he is now is very, very big partly because I was 13 when I first created him and the basic structure of his story and I was very inexperienced tho. He was a very edgy character, mad at the world, ready to kill and all that stuff because of what happened to him (he was a good boy deep down, but he had to grow a veeery thick skin to deal with what happened to him and all that).
The story hasn't changed much, but as I started writing more about the character and the story in detail he evolved a lot and didn't do a lot of stuff he did back then.
Every character has changed a lot since their creation tho. A character of mine (ginger, a girl who has already appeared) was created just because I wanted to create a lesbian that would like another character in the story. Now she's one of my favourites in regards of character development, she's grown miles from that flat beginning (she's still very very very gay tho, that didn't change one bit x'D).
All the villains have changed a lot as well. At first I only knew what they had to do and placed one dimensional characters in those roles. Then, again, I started writing about them and they became waaay more complex (and surprised me a LOT sometimes x'D once they're their own people they do unexpected stuff, it be like that).
There's one character who's an exception tho. She's the one who has changed the least, I think. Everything was kinda set from the beginning - I added a lot of details, changed her backstory a bit, more character traits, more depth in general to the character... But all her core traits were already perfectly stablished since the beginning (she just came to my house one day, kicked down the door and said "I'm your new forever fave now", basically hahahahaha).